A common method to connect the conductor pattern on a circuit card to outside circuits is by means of two part connectors, one half of which is mounted close to an edge of the circuit card while the other half is mounted in a frame or an apparatus cabinet.
In earlier known arrangements of this kind, the connector is fixed to the circuit card by means of mounting hardware (screws, rivets) which pass through mounting holes in the connector and through corresponding holes in the circuit card. The holes which have to be made in the circuit card will often be placed too close to the edge of the card in the connectors which are common today. Therefore there is a considerable risk that the card will break or splinter. Besides, the punchings close to the edge of the circuit card act as kerfs. As the required force for pushing the circuit card into the connector as well as for pulling it out again is considerable, fractures arise very easily. Also dynamic strains arising for example during transport involve a considerable risk of damage to the attaching means of the connectors of the card.
It is very common to place two connectors side by side on a large-sized circuit card. These connectors mate with connectors which are fixed in a frame. Due to the characteristics of the material the tolerances when punching circuit cards are so great that it is difficult to obtain the required precision in the distance between the two connector halves which are fixed on the circuit card. This may cause contact pins to be damaged due to deficient fitting.